Archive for April, 2010

Meeting notes

Tuesday, April 20th, 2010

Last week was a very interesting week for our WebKit group in Igalia, a lot of things happened, we even found that a volcano explosion did not allow Philippe to come back from San Francisco, hopefully he will make it at the end of this week. Luckily enough Juanjo, Xan and me have tickets for one of the few airports not closed in Europe.

Regarding software, we had the incredible opportunity to meet with a lot of WebKit engineers in the WebKit Contributors Meeting, it was very interesting to attend to the discussions and comment about the current situation of the project with the people there. Personally I would stress the debates about: WebKit2, Javascript engine performance and hardware acceleration drawing. I’ve also spend some time with Eric creating a version of the new-run-webkit-tests for Gtk+, I still have to check the patch and upload it. We also participated in the green bots hackathon, which allowed Gtk+ bots to enter in the core bots group, it took a little bit more time but now it should be easier to control the bots. Related with WebKit we also met some people in the bay are that are using WebKitGTK+, it is nice to check how the work we are doing is useful for those products.

I’ve also attended the Linux Collaboration Summit (just after the WebKit Meeting), it was not a bad experience, Google gave us a Nexus One after all. I was at the MeeGo workgroup where Nokia and Intel presented their agendas for the platform. I also was at the Desktop workgroup, the main topic was desktop technologies and the integration with Internet services, it is going to be interesting to check how the desktop will evolve to integrate Internet services, and what role free software plays in that environment.

Of course I have to mention I really enjoyed the city, we did not have much time but Martin helped us to discover very nice places and food.

WebKit meeting next week and rendering

Friday, April 9th, 2010

Lately I’ve been checking the rendering code in WebKitGTK+, graphics are always very challenging. We want to check how to improve scrolling and rendering in general. Maybe some of the points are interesting for someone else or maybe you can send me some feedback about them:

  • I’ve used cairo-trace and cairo-perf-trace to check the performance of different backends doing a usual short browsing session (open slashdot and scroll) with Epiphany. I wanted to add Skia to the test because I wanted to compare with Chrome backend. Cairo Skia backend does not look well maintained, I had to change some code in order to compile it, but it worked eventually. The results are interesting because shows that Xlib backend is faster (probably accelerated operations) than Skia and Skia is a little bit faster than the Cairo image backend but quite similar, both probably running on the CPU:
    [ # ]  backend                         test   min(s) median(s) stddev. count
    [  0]     null                     epiphany    0.644    0.652   2.06%    6/6
    [  0]       gl                     epiphany    7.121    8.770   8.91%   15/15
    [  0]     skia                     epiphany    2.106    2.110   0.11%    5/6
    [  0]     xlib                     epiphany    1.874    1.903   1.41%    5/6
    [  0]    image                     epiphany    2.154    2.180   1.09%    6/6
    [  0]  image16                     epiphany    3.721    3.752   0.59%    6/6
    

    If this is correct we have to look inside WebKit for improvements, which means we have to review the rendering process carefully.

  • After checking the patches for the tiled backing store I’ve implemented a tiled backing store for WebKitGTK+ in a branch of a local repository in Igalia. It still has some pending work (graphic context not correctly used in forms, frames are not supported, threading, resizes, etc.). Results regarding performance are not the expected ones but it works and we can check the performance, conclusion is still not clear, blit is fast but we need to improve the tiles rendering. I think we have to be very sure that we are improving the situation when adding complex code, so there is still work here to show it makes sense.

I would like to add that cairo-trace is an awesome tool, Cairo people deserve a lot of kudos for implementing it. I will use cairo-trace to check the tiled backing store and how the solution of the form controls rendering behaves with regard to performance.

Regarding the other part of the topic, next week some of us will be in San Francisco for the Webkit meeting, we will also attend the Linux Collaboration Summit and meet some people there; so if you are in the bay area and you want to have a drink just sent us an email. With the last WebKit2 announcement I think it would be a very interesting meeting.

I almost forgot, our WebKit team in Igalia has grown and we have more motivated people working with us (currently Xan, Philippe, Sergio, Mario, Juanjo and me, and Diego doing his internship), this is good because we could work in more interesting topics inside the project.